1 files changed, 114 insertions, 0 deletions
diff --git a/Core/Util/SecureRandom.php b/Core/Util/SecureRandom.php
new file mode 100644
index 0000000..841b9af
--- /dev/null
+++ b/Core/Util/SecureRandom.php
@@ -0,0 +1,114 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Security\Core\Util;
+
+use Psr\Log\LoggerInterface;
+
+/**
+ * A secure random number generator implementation.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ * @author Johannes M. Schmitt <schmittjoh@gmail.com>
+ */
+final class SecureRandom implements SecureRandomInterface
+{
+    private $logger;
+    private $useOpenSsl;
+    private $seed;
+    private $seedUpdated;
+    private $seedLastUpdatedAt;
+    private $seedFile;
+
+    /**
+     * Constructor.
+     *
+     * Be aware that a guessable seed will severely compromise the PRNG
+     * algorithm that is employed.
+     *
+     * @param string          $seedFile
+     * @param LoggerInterface $logger
+     */
+    public function __construct($seedFile = null, LoggerInterface $logger = null)
+    {
+        $this->seedFile = $seedFile;
+        $this->logger = $logger;
+
+        // determine whether to use OpenSSL
+        if (defined('PHP_WINDOWS_VERSION_BUILD') && version_compare(PHP_VERSION, '5.3.4', '<')) {
+            $this->useOpenSsl = false;
+        } elseif (!function_exists('openssl_random_pseudo_bytes')) {
+            if (null !== $this->logger) {
+                $this->logger->notice('It is recommended that you enable the "openssl" extension for random number generation.');
+            }
+            $this->useOpenSsl = false;
+        } else {
+            $this->useOpenSsl = true;
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function nextBytes($nbBytes)
+    {
+        // try OpenSSL
+        if ($this->useOpenSsl) {
+            $bytes = openssl_random_pseudo_bytes($nbBytes, $strong);
+
+            if (false !== $bytes && true === $strong) {
+                return $bytes;
+            }
+
+            if (null !== $this->logger) {
+                $this->logger->info('OpenSSL did not produce a secure random number.');
+            }
+        }
+
+        // initialize seed
+        if (null === $this->seed) {
+            if (null === $this->seedFile) {
+                throw new \RuntimeException('You need to specify a file path to store the seed.');
+            }
+
+            if (is_file($this->seedFile)) {
+                list($this->seed, $this->seedLastUpdatedAt) = $this->readSeed();
+            } else {
+                $this->seed = uniqid(mt_rand(), true);
+                $this->updateSeed();
+            }
+        }
+
+        $bytes = '';
+        while (strlen($bytes) < $nbBytes) {
+            static $incr = 1;
+            $bytes .= hash('sha512', $incr++.$this->seed.uniqid(mt_rand(), true).$nbBytes, true);
+            $this->seed = base64_encode(hash('sha512', $this->seed.$bytes.$nbBytes, true));
+            $this->updateSeed();
+        }
+
+        return substr($bytes, 0, $nbBytes);
+    }
+
+    private function readSeed()
+    {
+        return json_decode(file_get_contents($this->seedFile));
+    }
+
+    private function updateSeed()
+    {
+        if (!$this->seedUpdated && $this->seedLastUpdatedAt < time() - mt_rand(1, 10)) {
+            file_put_contents($this->seedFile, json_encode(array($this->seed, microtime(true))));
+        }
+
+        $this->seedUpdated = true;
+    }
+}